Standardized low-molecular-weight heparin bridging regimen in outpatients on oral anticoagulants undergoing invasive procedure or surgery: an inception cohort management study

BACKGROUND

Bridging therapy with low-molecular-weight heparin is usually recommended in patients who must stop oral anticoagulants before surgical or invasive procedures. To date, there is no universally accepted bridging regimen tailored to the patient's thromboembolic risk. This prospective inception cohort management study was designed to assess the efficacy and safety of an individualized bridging protocol applied to outpatients.

METHODS AND RESULTS

Oral anticoagulants were stopped 5 days before the procedure. Low-molecular-weight heparin was started 3 to 4 days before surgery and continued for 6 days after surgery at 70 anti-factor Xa U/kg twice daily in high-thromboembolic-risk patients and prophylactic once-daily doses in moderate- to low-risk patients. Oral anticoagulation was resumed the day after the procedure with a boost dose of 50% for 2 days and maintenance doses afterward. The patients were followed up for 30 days. Of the 1262 patients included in the study (only 15% had mechanical valves), 295 (23.4%) were high-thromboembolic-risk patients and 967 (76.6%) were moderate- to low-risk patients. In the intention-to-treat analysis, there were 5 thromboembolic events (0.4%; 95% confidence interval, 0.1 to 0.9), all in high-thromboembolic-risk patients. There were 15 major (1.2%; 95% confidence interval, 0.7 to 2.0) and 53 minor (4.2%; 95% confidence interval, 3.2 to 5.5) bleeding episodes. Major bleeding was associated with twice-daily low-molecular-weight heparin administration (high-risk patients) but not with the bleeding risk of the procedure.

CONCLUSIONS

This management bridging protocol, tailored to patients' thromboembolic risk, appears to be feasible, effective, and safe for many patients, but safety in patients with mechanical prosthetic valves has not been conclusively established.

Atherosclerotic and thrombophilic risk factors in patients with recurrent central retinal vein occlusion

PURPOSE

Atherosclerotic and thrombophilic risk factors may be causes of central retinal vein occlusion (CRVO). The aim of this study was to evaluate the prevalence of the aforesaid risk factors in patients with recurrent CRVOs and patients with a single episode of CRVO.

METHODS

Seventeen patients with recurrent CRVO and 30 with a single episode of CRVO were enrolled. The atherosclerotic risk factors investigated were hypertension, diabetes, smoking, and dyslipidemia. Specific laboratory tests for the following thrombophilic markers were performed: homocystinemia (Hcy), lipoprotein (a), factor VIII, factor II G20210A and factor V G1691A polymorphisms, lupus anticoagulant, anticardiolipin antibodies, plasminogen activator inhibitor-1, and deficit of vitamins B6, B12, and folic acid. A multivariate analysis, adjusted for age, gender, traditional and thrombophilic risk factors, was performed. Statistical significance was set at p<or=0.05.

RESULTS

Hypercholesterolemia, hypertriglyceridemia, fasting, and postmethionine hyperhomocysteinemia (HHcy) were more prevalent in recurrent CRVO patients (p<0.001, p<0.001, p=0.006, and p=0.005, respectively). At multivariate analysis, hypercholesterolemia (OR: 5.04, 95% CI 1.39-18.17; p=0.025), hypertriglyceridemia (OR: 5.60, 95% CI 1.52-20.61; p=0.017), fasting HHcy (OR: 5.77, 95% CI 1.39-23.89; p=0.028), and postmethionine HHcy (OR: 10.88, 95% CI 2.50-47.42; p=0.002) were found to be significantly associated with recurrent CRVO.

CONCLUSIONS

Dyslipidemia and hyperhomocysteinemia are independent risk factors for the occurrence of recurrent CRVO. A complete assessment of atherosclerotic and thrombophilic risk factors in CRVO patients. In addition, the need for a specific treatment is suggested.

Retrievable vena cava filters: Key considerations

Retrievable filters are a new generation of inferior vena cava (IVC) filters and represent an attractive option because they may be either left in place permanently or safely retrieved after a quite long period when they become unnecessary. In this review the currently available literature regarding retrievable IVC filters is summarized and their efficacy and safety is discussed. Moreover, the appropriate indications for their use are reviewed. Retrievable filters are becoming safer and easier to use; in fact the bioengineering research has optimized the technical characteristics of these devices, in order to reduce the incidence of possible complications. However, there are important unresolved issues, including the appropriate maximum implantation time, the possibility to safely and efficaciously remove the filters without being compromised by entrapped clots, and the use of anticoagulation during the implantation and periremoval periods. Large prospective cohort studies or randomized trials are strongly warranted to definitely clarify the beneficial role of these devices.

Different methodologies for evaluating the effect of clopidogrel on platelet function in high-risk coronary artery disease patients

BACKGROUND

Two point-of-care (POC) systems have been recently proposed as rapid tools with which to evaluate residual platelet reactivity (RPR) in coronary artery disease (CAD) patients.

OBJECTIVES AND METHODS

We compared Platelet Function Analyzer-100 (PFA-100) closure times (CTs) by collagen/adenosine 5'-diphosphate (ADP) (C/ADP CT) cartridge and the VerifyNow P2Y12 Assay (VerifyNow) with light transmission aggregation (LTA) induced by 2 and 10 micromol L(-1) ADP in 1267 CAD patients on dual antiplatelet therapy who underwent percutaneous coronary intervention. We also performed the vasodilator-stimulated phosphoprotein (VASP) phosphorylation assay by cytofluorimetric analysis in a subgroup of 115 patients.

RESULTS

Cut-off values for identifying RPR were: > or = 54% and > or = 66% for LTA induced by 2 and 10 micromol L(-1) ADP respectively, and > or = 264 P2Y12 Reaction Units (PRU) for VerifyNow. The cut-off for PFA-100 C/ADP CT was > or = 68 s. RPR was detected in 25.1% of patients by 2 mumol L(-1) ADP-induced LTA (ADP-LTA), in 23.2% by 10 micromol L(-1) ADP-LTA, in 24.4% by PFA-100, and in 24.7% by VerifyNow. PFA-100 results did not parallel those obtained with LTA. VerifyNow showed a significant correlation (rho = 0.62, P < 0.001) and significant agreement (k = 0.34, P < 0.001) with LTA induced by 2 micromol L(-1) ADP. The correlation was similar but the agreement was better between VerifyNow and 10 micromol L(-1) ADP-LTA (rho = 0.64, P < 0.0001; k = 0.43, P < 0.001). Significant relationships were found between VASP platelet reactivity index and both ADP-LTA and VerifyNow. PFA-100 C/ADP CT did not significantly correlate with any of the other assays.

CONCLUSIONS

Our results show a significant correlation between LTA and VerifyNow but not the PFA-100 C/ADP assay. Clinical validation studies for POC systems are necessary.

Renal transplant recipients are at high risk for both symptomatic and asymptomatic deep vein thrombosis

BACKGROUND

Venous thromboembolism (VTE) is one of the thrombotic complications that can occur in patients receiving renal transplantation (RT). The prevalence of VTE in RT patients is, however, undefined.

OBJECTIVES

To evaluate the rate of a first episode of VTE in a series of 538 consecutive RT recipients admitted to our institution, the timing of occurrence of the thromboembolic events after transplantation, and the rate of recurrence after thromboprophylaxis withdrawal. Risk factors for recurrence were also evaluated, particularly in relation to the type of the first event (symptomatic or asymptomatic).

RESULTS

During follow-up, 47 of 518 patients (28 males, 19 females; 9.1%) developed a first episode of VTE at a median time of 17 months (range 1-165 months) after kidney transplantation. Cancer was associated with the occurrence of VTE (odds ratio 4.8). Seventeen of 43 patients (39.5%) with deep vein thrombosis were asymptomatic and the diagnosis was made during routine ultrasound examination. Twenty-two patients (46.8%) experienced a recurrence of VTE. A relevant rate of recurrence was documented amongst patients with a first episode of both symptomatic (53%) and asymptomatic (23.5%) VTE.

CONCLUSION

This study confirms that RT patients are at high risk of symptomatic and asymptomatic VTE and that this risk persists even after several years. Patients who experience VTE are at high risk of recurrence after thromboprophylaxis withdrawal.

Homocysteine-Lowering Therapy and Carotid Intima-Media Thickness in Renal Transplant Recipients

The aim of this study was to document, in hyperhomocysteinemic renal transplant recipients, the effect of vitamin supplementation on carotid intima-media thickness (cIMT). Fifty-six hyperhomocysteinemic stable renal transplant recipients were randomly assigned to either vitamin supplementation (group A) or placebo treatment (group B). All patients underwent high-resolution B mode ultrasound to measure IMT of common carotid arteries before and after 6 months of vitamin supplementation. In group A, cIMT significantly decreased after treatment, whereas no significant changes were observed in group B. In conclusion, our results demonstrate a beneficial effect of the treatment of hyperhomocysteinemia by vitamin supplementation on an early sign of atherosclerosis in a group of renal transplant recipients.

PAI-1 and homocysteine, but not lipoprotein (a) and thrombophilic polymorphisms, are independently associated with the occurrence of major adverse cardiac events after successful coronary stenting

OBJECTIVE

To evaluate the role of factor V Leiden, prothrombin G20210A polymorphism, plasminogen activator inhibitor type 1 (PAI-1) 4G/5G polymorphism, PAI-1, homocysteine, and lipoprotein (a) (Lp(a)) in the occurrence of major adverse cardiac events (MACE) in patients with acute coronary syndromes who underwent coronary stenting.

DESIGN

520 patients (375 men and 145 women) with acute coronary syndromes and 520 age and sex matched controls were enrolled. MACE were recorded for 109 patients. Heterozygosity for factor V Leiden, prothrombin G20210A polymorphism, and 4G/5G polymorphism did not significantly differ between patients with and without MACE. A significantly higher percentage of patients with increased homocysteine (28% v 19%, p < 0.001) and PAI-1 concentrations (25% v 16%, p < 0.001) had MACE with respect to those who did not. In Kaplan-Meier survival analysis, the overall risk of MACE was significantly higher among patients with increased PAI-1 (p = 0.006) and homocysteine concentrations (p = 0.04). Cox regression analysis adjusted for age, sex, traditional cardiovascular risk factors, renal function, systolic left ventricular function, the number of stenosed vessels, and history of percutaneous coronary intervention or coronary artery bypass grafting showed that homocysteine (odds ratio 7.5, 95% confidence interval (CI) 1.1 to 57.7, p < 0.05) and PAI-1 concentrations (odds ratio 5.3, 95% CI 1.2 to 23.8, p < 0.05) within the fifth quintile (with respect to the first) were significant and independent risk factors for the future occurrence of MACE.

CONCLUSIONS

Increased PAI-1 and homocysteine concentrations are independent risk factors for MACE after successful coronary stenting, whereas Lp(a) and thrombophilic polymorphisms are not predictive.

Venous Thromboembolism in Renal Transplant Recipients: High Rate of Recurrence

Few data are available on the incidence of venous thromboembolism occurring in renal transplant recipients and optimal duration of oral anticoagulant therapy after thrombotic episode. Our study was performed to evaluate the risk of thrombosis recurrence in patients developing a first episode. Among 484 renal transplant patients 34 (7%) developed a first thromboembolism and were referred to the Thrombosis Centre: 28 patients (group 1) were prospectively studied, after stopping anticoagulants. Group 1 was compared with a group of 84 patients without an history of renal disease who had suffered from a first thrombotic episode and were matched for age, sex, and type of thrombotic event (group 2). During follow-up, 14/28 group 1 patients and 8/84 group 2 patients experienced thrombotic recurrence (P = .0001). Our data outline the high risk of recurrence in renal transplant recipients. Strategies for recurrence prevention are needed taking into account the high bleeding risk of anticoagulants in renal transplant patients.

Cardiovascular and thrombophilic risk factors for idiopathic sudden sensorineural hearing loss

BACKGROUND

In recent years there has been a significant increase in the diagnosis of sudden sensorineural hearing loss (SSHL) in western, countries with an incidence of 20 of 100,000 people affected every year. No clear causes for this disease have been found thus far, but cochlear ischemia has been hypothesized in patients in whom an infectious episode or acoustic neurinoma have been excluded.

OBJECTIVES

The aim of this case-control study was to investigate a number of acquired and inherited thrombophilic risk factors [antithrombin, protein C and S; factor V (FV) Leiden, FII polymorphism; lupus anticoagulant (LA); anticardiolipin (aCL) antibodies; fasting homocysteine (Hcy); lipoprotein(a) (Lp(a)); plasminogen activator inhibitor-1 (PAI-1)] in addition to cardiovascular risk factors in patients with idiopathic SSHL (ISSHL).

PATIENTS AND METHODS

We investigated 155 patients (67 male/88 female; age: 55 (range 19-79 years) with a diagnosis of ISSHL within 30 days from the onset of symptoms, and 155 controls (67 male/88 female; age 54 (range 19-78 years). Fasting Hcy levels were significantly higher in patients than in controls [11.6 (6.7-60) micromol/L vs. 8.7 (5.0-24) micromol/L] as well as PAI-1 levels [19 (2-95) mg/dL vs. 14.5 (4.0-87) mg/dL]. Lupus anticoagulant was present in 13 of 155 (8.4%) patients; 20 patients (12.9%) had positivity of aCL (four IgM and 16 IgG). In no patient was a deficiency of physiological clotting inhibitors antithrombin, protein C and protein S found. No significant differences between patients and controls were observed for Lp(a) plasma levels [111 (1-1146) mg/L vs. 103 (11-695) mg/L] and for the presence of FV Leiden (4.5% vs. 4.5%) and FII variant G20210A (3.8% vs. 3.2%).

RESULTS AND CONCLUSIONS

Independent risk factors for ISSHL at the multivariate analysis (adjusted for age, sex and the traditional cardiovascular risk factors) were the positivity of aCL: OR 5.6 (95% CI 2.0-15.3); cholesterol levels within the second and third tertiles (with respect to the first tertile): T2 = OR 4.8 (95% CI 1.9-12.6)/T3 = OR 19 (95% CI 7-50.1); PAI-1 and Hcy levels within the third tertile (with respect to the first tertile): OR 20 (95% CI 7.8-78) and OR 4.0 (95% CI 2.0-8.1), respectively. These preliminary data suggest that hypercholesterolemia, hyperhomocysteinemia, elevated PAI-1 levels and anticardiolipin antibodies are associated with ISSHL, so indirectly supporting the hypothesis of a vascular occlusion in the pathogenesis of the disease.

Relevance of post-methionine homocysteine and lipoprotein (a) in evaluating the cardiovascular risk in young CAD patients

BACKGROUND

Aims of our study were to evaluate the prevalence of high lipoprotein (a) [Lp(a)] and homocysteine levels - both in the fasting state (FHcy) and post-methionine (PMHcy) - in young coronary artery disease (CAD) patients, and to investigate the role of genetic and environmental factors for hyperhomocysteinaemia.

MATERIALS AND METHODS

We studied 140 patients with angiographically documented CAD (24 women </= 55 years and 116 men </= 50 years) and 140 healthy subjects as controls.

RESULTS

Both FHcy [13.2 (5.4-45.8) vs. 9.0 (5.1-24) micromol L(-1)); P < 0.0001] and PMHcy [(39.4 (9.0-66.4) vs. 25.2 (16.4-33.9); P < 0.0001] were significantly higher in patients than in controls. Lp(a) levels were significantly higher in patients than in controls (200 (3-1486) mg L(-1) vs. 97 (10-412) mg L(-1); P < 0.0001). At the multivariate analysis, adjusted for the classical cardiovascular risk factors and creatinine levels, the OR (95% CI) for CAD at young age significantly increased in the fourth quartile of the distribution of FHcy, PMHcy and Lp(a) levels [FHcy: 14.9 (4.1-58), P < 0.0001; PMHcy: 19.2 (4.0-86.3); P < 0.0001; Lp(a): 19.6 (4.7-78.6): < 0.0001]. Vitamin deficiencies were detected in 28/140 (20%) patients. The prevalence of the homozygous C677T (+/+) methylenetetrahydrofolatereductase genotype was higher, but not significantly different, in patients (22.8%) than in controls (18.6%). The allele frequency of the 844ins68 insertion variant in the cystathionine beta-synthase gene was 0.08 in the control group and 0.06 in the patient group.

CONCLUSIONS

Results of the present study indicate the usefulness of including fasting and post-methionine Hcy, and Lp(a) determination in the diagnostic panels of young CAD patients, in order to obtain a better assessment of their cardiovascular risk profile.

ACE DD genotype: an independent predisposition factor to venous thromboembolism

BACKGROUND

The renin angiotensin system affects haemostasis through different mechanisms; data on the possible role of angiotensin-converting enzyme I/D polymorphism in the pathogenesis of deep venous thrombosis are conflicting, and no information is available regarding the A1166C polymorphism of the angiotensin type 1 receptor gene. In order to investigate this issue, angiotensin-converting enzyme and AT1R polymorphisms were genotyped in 336 consecutive venous thromboembolism patients and 378 controls.

MATERIALS AND METHODS

Haemostasis-related risk factors have been evaluated by routine tests. Factor V Leiden, Factor II (G20210A), angiotensin-converting enzyme (I/D), and angiotensin type 1 receptor (A1166C) polymorphisms have been identified by molecular analysis.

RESULTS

We documented a significant association between angiotensin-converting enzyme DD genotype and venous thromboembolism (OR=2.19 95%CI 1.51-3.17 adjusted for acquired and haemostasis-related risk factors, P<0.0001); in patients with haemostasis-related risk factors, angiotensin-converting enzyme DD genotype modified the risk of venous thromboembolism in hyperhomocysteinaemic and Factor V Leiden patients and was associated with the risk of recurrent venous thromboembolism (OR=1.83 95%CI 1.06-3.17 P=0.03). In patients without haemostasis-related risk factors the angiotensin-converting enzyme DD genotype was still an independent predictor of venous thromboembolism (OR=3.29 95%CI 2.17-4.98 adjusted for acquired risk factors, P<0.0001). No significant association between the angiotensin type 1 receptor CC genotype and venous thromboembolism was found.

CONCLUSIONS

This study shows that angiotensin-converting enzyme DD genotype represents a susceptibility marker of thrombosis in subjects apparently without predisposing factors and traditional thrombophilic alterations, and increases the risk of venous thromboembolism in subjects in whom a thrombogenic condition occurs. Moreover, angiotensin-converting enzyme DD genotype may be considered a new predisposing factor to venous thromboembolism recurrence.

Tissue factor and tissue factor pathway inhibitor levels in unstable angina patients during short-term low-molecular-weight heparin administration

High tissue factor (TF), tissue factor pathway inhibitor (TFPI) levels and a hypercoagulability state have been documented in unstable angina patients. We evaluated whether short-term enoxaparin administration (100 IU/kg b.i.d. for 3 d) reduces the high TF levels and the hypercoagulability state, and whether it influences the fibrinolytic system in 20 unstable angina patients. On d 3, we observed a significant reduction in TF levels both 1 h and 4 h after the morning injection (-25.6% and -21.7%; P < 0.001 respectively) in comparison with the base-line levels. Both 1 and 4 h after the morning injection on the d 3, TFPI levels significantly (P < 0.001) increased (+96.4%, +96.9% respectively) with respect to the base-line values. After enoxaparin administration, at all observation times, thrombin-antithrombin complexes and prothrombin fragment F1 + 2 levels were significantly (P < 0.001) lower with respect to base-line levels. We observed a slight but significant increase in tissue plasminogen activator antigen levels in preinjection samples, as well as 1 h and 4 h after enoxaparin administration, in comparison with the base-line values. This study provides evidence that low-molecular-weight heparin (LMWH) administration, in addition to a reduction of hypercoagulability and a mild fibrinolytic activation, is associated with decreased TF levels, so indicating a novel mechanism of interference of LMWH with the haemostatic system.

Need of more frequent International Normalized Ratio monitoring in elderly patients on long-term anticoagulant therapy after influenza vaccination

Previous findings suggest the safety of influenza vaccination for patients on oral anticoagulant therapy (OAT). However, some studies reported a moderate reduction or increase of the anticoagulation. We assessed the effect of influenza vaccination on anticoagulation levels. Seventy-three patients on stable long-term OAT were recruited. Patients were compared with a control group of 72 patients observed during the same period. No differences in the anticoagulation levels were found in patients and in controls during the 3 months before and after the vaccination. However, in patients older than 70 years we observed a reduction of anticoagulation intensity achieved in the month after the vaccination, with a prolonged time spent below the therapeutic range (10% before and 27% after, P = 0.001), and this behaviour was still observed 3 months after vaccination. Influenza vaccination is safe in patients on OAT, but it is associated with a slight reduction in warfarin effect in the elderly, suggesting the need of more frequent International Normalized Ratio monitoring after vaccination in these subjects.

Comparison of three methods for total homocysteine plasma determination

Hyperhomocysteinemia is a well established risk factor for atherothrombotic disease, and the request for homocysteine determinations and the number of laboratories that need to perform this assay to assess individual risk profile is increasing. Different methods to evaluate homocysteine plasma levels are at present available. In the present study three methods, an in-house high-pressure liquid chromatographic (HPLC) method (considered as reference method) and two commercial immunoassays, an enzyme-linked immunoassay (EIA) and an automated fluorescence polarization immunoassay (FPIA), were used to measure homocysteine plasma levels in 100 samples. The median of homocysteine plasma levels obtained by HPLC was 9.0 micromol/L (range 4.2-23.0); the median of values obtained by EIA and FPIA were 10.6 micromol/L (range 3.3-21.5) and 9.6 micromol/L (4.8-20.2), respectively. The FPIA method showed the lowest within-run and between-run coefficients of variation (3.6% and 4.1%, respectively). There was a significant correlation between EIA and HPLC (r=0.81; p<0.0001), and between FPIA and HPLC (r=0.85; p<0.0001). The Bland-Altman analysis showed that FPIA agreed best with HPLC; EIA displayed a relatively wide scatter of difference data points. The present results indicate that the technological characteristics of the FPIA assay make this method suitable for the determination of Hcy in clinical laboratories.

D-dimer increase after percutaneous transluminal angioplasty and clinical recurrence after primary revascularization in acute myocardial infarction? A pilot study

It has been reported that the increase of plasminogen activator inhibitor-1 activity immediately after elective coronary angioplasty is related to subsequent clinical recurrence in patients with chronic coronary artery disease. The aims of our study were to evaluate the behavior of plasminogen activator inhibitor-1 and D-Dimer after revascularization in acute myocardial infarction patients treated with angioplasty and stenting and if this behavior is predictive of subsequent clinical recurrence. D-Dimer and plasminogen activator inhibitor-1 activity were evaluated in two groups of patients. Group 1 consisted of 54 consecutive patients undergoing primary angioplasty for acute myocardial infarction and Group 2 consisted of 48 patients undergoing elective angioplasty. Patients underwent control coronary angiography only in the case of clinical recurrence and/or positivity of provocative tests. D-Dimer and plasminogen activator inhibitor-1 baseline levels were significantly higher in group 1 than in group 2 (P<0.0005 and P<0.05, respectively). The percentage of group 1 patients with a post-procedural increase in D-Dimer was significantly higher among those with subsequent clinical recurrence with restenosis (61%) than among those with no recurrence (25%, P<0.05). No difference was observed in group 2. The percentage of group 2 patients in whom no decrease of plasminogen activator inhibitor-1 was observed after angioplasty was significantly higher (83%) among those with subsequent recurrence than among those with no recurrence (38%, P<0.05). This pattern was not observed in group 1. In conclusion, the role of early changes in plasminogen activator inhibitor-1 in predicting clinical recurrence after primary angioplasty in acute myocardial infarction patients is less clear than that observed after elective angioplasty. A significant role seems to be played by a more-marked clotting activation with increased fibrin formation.

Postprocedural PAI-1 activity is a risk marker of subsequent clinical restenosis in patients both with and without stent implantation after elective balloon PTCA

Stent implantation after balloon dilation of coronary arteries has improved clinical prognosis in patients undergoing transluminal coronary angioplasty (PTCA), but late restenosis remains a relevant problem. A previous study has indicated that PAI-1 activity changes immediately after PTCA without stent implantation are predictive of clinical restenosis. The present study was aimed to investigate the early PAI-1 changes and fibrin formation in patients undergoing elective PTCA with stent implantation. PAI-1 activity and D-dimer plasma levels were evaluated in two groups of patients (G1 underwent only elective balloon PTCA and G2 underwent elective PTCA with stent implantation) before and after the procedure. At the end of the procedure, PAI-1 activity significantly decreased, while D-dimer levels significantly increased in both groups. Post-PTCA D-dimer levels in the group with stent implantation were significantly higher than in the other group (P<.05). In both groups of patients, the post-PTCA PAI-1 activity was higher in patients with subsequent clinical recurrence with restenosis (P<.005 in G1 and P<.0005 in G2) than in those without, whereas no differences were found in D-dimer levels. In conclusion, our results demonstrate that fibrin formation assessed by D-dimer levels is enhanced by stent implantation. However, this behaviour is not related, differently from PAI-1 changes, to subsequent occurrence of clinical restenosis.